Iran will return to talks with the International Atomic Energy Agency next month, the UN nuclear watchdog said on Friday, the latest push to seek a peaceful end to a dispute that has raised fears of a new Middle East war.

The IAEA announcement came days after US President Barack Obama's re-election, which some analysts say may give fresh impetus to diplomatic efforts to end to a decade-old standoff with a country the West accuses of working towards nuclear weapons capability.

In a stark reminder of how tensions could escalate, the Pentagon said on Thursday that Iranian warplanes fired at an unarmed US drone in the Gulf last week.

The IAEA said it hoped the talks in Tehran on Dec. 13 would produce an agreement to allow it to resume a long-stalled investigation into possible military aspects of Iran's nuclear program.

The agency says it has "credible information indicating that Iran had
carried out activities relevant to the development of a nuclear
explosive device" and wants Tehran to give it access to sites, officials
and documents to clarify the issue.

A Western diplomat was skeptical, noting that the talks would only take place after the next meeting of the IAEA's 35-nation governing board.

"So it is the usual scenario: defer criticism now by promising something later. Something that has failed to materialize the last four times," the envoy said.

A series of meetings since early this year, the last one in August, failed to make concrete progress.

Israel, assumed to be the Middle East's only nuclear-armed power, has threatened military action if it looks like Tehran is close to getting nuclear weapons capability.

EU's Ashton describes meeting as "initial step"

The IAEA's talks with Iran are separate from Tehran's nuclear discussions with six world powers - the United States, Russia, China, Britain, France and Germany - which resumed in April but have also so far failed to reach any breakthrough.

European Union foreign policy chief Catherine Ashton - who represents the powers in talks with Iran - sees the new IAEA-Iran meeting as long overdue.

It "could be an initial step on the path to resolve outstanding issues," Maja Kocijancic, Ashton's spokeswoman, said, adding that Iran had so far failed to cooperate in substance.

She reiterated concerns about the Parchin military site, which the IAEA wants to visit as part of its inquiry and where Western diplomats suspect Iran is now trying to clean up any evidence of past illicit nuclear-related activity.

The IAEA mission is likely to be headed by Deputy Director General Herman Nackaerts, the chief UN nuclear inspector, diplomatic sources said.

Iran's ambassador to the IAEA, Ali Asghar Soltanieh, was not immediately available for comment.